Home range size, space use and resource selection of griffon vultures in an insular environment

Abstract

The extent of home ranges of griffon vultures (Gyps fulvus) was studied on Crete (Greece) during 2005–2015 by monitoring 27 individuals with very high frequency radio‐telemetry. Radio‐tagged birds were followed for an average period of 13.1 months (n = 7–22), where a total of 1615 days of fieldwork produced 4420 radiolocations (x = 163.5 radiolocations per tagged bird, n = 142–328). Overall, the mean home range and mean core area of griffon vultures were estimated at 1560 ± 140 km2 (KDE 95%) and 373 ± 36 km2 (KDE 50%) respectively with significant age‐related differences within seasons. Immature griffon vultures ranged on average about double the area ranged by adults in winter and occupied significantly larger core areas. The home range overlap in per cent and utilization distribution between adult and immature birds was also significantly less in winter than in summer. Foraging griffon vultures avoided northern slopes with unfavourable flight conditions and selected sites within rangelands with low diurnal temperature variations where overwintering livestock and suitable nesting cliffs occur. Foraging adults were restricted to the vicinity of the breeding colonies and favoured sites away from urban zones. In contrast, immature griffon vultures selected pastoral zones in marginal areas with mild winters and rugged terrain. The existence of predictable food sources in combination with suitable roosting sites and favourable flight conditions were the main factors differentiating the space‐use pattern between the two age classes. We recommend that apart from the maintenance of traditional farming practices, sites, such as large communal roosts and flight corridors or entire ‘hotspot’ activity zones of immature birds, should be taken into account in conservation planning and sensitivity mapping for the species.

New insight into spatial ecology of Griffon Vulture (Gyps fulvus) on the Balkans provides opportunity for focusing conservation actions for a threatened social scavenger

“…Those researchers have used ringing and radio transmitters fitted to single birds; metal and colour ring recovery data and wing tagging have all proven that Griffon Vultures and especially the young individuals carry out long-distance migrations. More recently, GPS-based studies on the local territory use and movements of Griffon Vultures from some countries on the Balkans, similar to studies that have been conducted earlier on the Iberian Peninsula and elsewhere ( García-Ripollés et al 2011 , Bahat et al 2001 ), have also been published for Greece (Crete) ( Xirouchakis et al 2021 ), Serbia ( Hribsek et al 2021 ), Eastern Alps and Croatia ( Genero et al 2020 ) and Bulgaria ( Peshev et al 2018 , Stoynov et al 2018 ). However, there is still no comprehensive study and detailed analysis of the use of the entire territory, (cross)movements, spatial behaviour and sojourn patterns of the species from the Balkan Peninsula in a regional context.…”

Anthropogenic Drivers Leading to Population Decline and Genetic Preservation of the Eurasian Griffon Vulture (Gyps fulvus)

“…The extension of the feeding area of the Eurasian griffon is proportional to carcass availability and generally involves a territory of ~25 km in radius in the mainland [63] and of ~9 km in the islands [64], starting from the centre of its nesting site. Every day, it carries The Eurasian griffon is socially monogamous and shows high nest-site fidelity.…”

“…The extension of the feeding area of the Eurasian griffon is proportional to carcass availability and generally involves a territory of~25 km in radius in the mainland [63] and of~9 km in the islands [64], starting from the centre of its nesting site. Every day, it carries out flights such as mopping-up for control and identification of carcasses in the territory, flying much higher if the density of the ungulate population is very low [65].…”

Seasonal and age-specific dynamics of the Griffon Vulture’s home range and movements in the Eastern Rhodopes

“…Vulture movement data is used to assess the effectiveness of protected areas, the risk of collision with human-made infrastructure, detect poisoning incidents and identify mortality hotspots and priority areas for conservation (Alarcon & Lambertucci 2018). Studies on the Griffon Vulture's movements were already conducted in Spain (García-Ripollés et al 2011), Israel (Bahat et al 2001, Crete (Xirouchakis et al 2021), on the Balkans (Peshev et al 2021), Bulgaria (Peshev et al 2018), Serbia (Hribsek et al 2021), Eastern Alps and Croatia (Genero et al 2020). However, the increasing Griffon Vulture population in the trans-border Rhodope Mountains in Bulgaria and Greece has not yet been studied.…”